Known door latch operation devices for a vehicle are disclosed in Japanese Patent Laid-Open Publication No. 2000-54708 and Japanese Patent Laid-Open Publication No. 2000-345752. The door latch operation device described in Japanese Patent Laid-Open Publication No. 2000-54708 includes a latch mechanism, an electric actuation mechanism, a mechanical operation member, and a mechanical identification operation member. The latch mechanism is provided on the vehicle door, which is adapted to be opened and closed relative to the vehicle body, for performing a latched condition in which the vehicle door is maintained at the closed condition relative to the vehicle body and an unlatched condition in which the vehicle door is capable of being opened relative to the vehicle body. The electric actuation mechanism operates the latch mechanism from the latched condition to the unlatched condition. The mechanical operation member provided in the vehicle compartment actuates the latch mechanism from the latched condition to the unlatched condition. The mechanical identification operation member provided outside the vehicle compartment actuates the latch mechanism from the latched condition to the unlatched condition.
The door latch operation device described in Japanese Patent Laid-Open Publication No. 2000-345752 includes a latch mechanism, an electric actuation mechanism, and a mechanical operation member. The latch mechanism is provided on the vehicle door which is adapted to be opened and closed relative to the vehicle body for performing a latched condition in which the vehicle door is maintained at the closed condition relative to the vehicle body and for performing the unlatched condition in which the vehicle door is to be opened relative to the vehicle body. The electric actuation mechanism actuates the latch mechanism from the latched condition to the unlatched condition. The mechanical operation member is provided in the vehicle compartment and actuates the latch mechanism from the latched condition to the unlatched condition.
This known door latch operation device further includes an engagement-disengagement mechanism linked to the electric actuation mechanism between the mechanical operation member and the latch mechanism. Through actuation of the engagement-disengagement mechanism by driving the electric actuation mechanism, two conditions are performed, namely a non-set condition in which the mechanical operation member and the latch mechanism are linked and a set condition in which the linkage between the mechanical operation member and the latch mechanism is released. The anti-theft performance of the vehicle is improved by performing the set condition so that the latch mechanism is not actuated to the unlatched condition by unjustly operating the mechanical operation member.
However, providing the engagement-disengagement mechanism between the mechanical operation member and the latch mechanism as in the foregoing known device, a switching mechanism cannot be operated from the set condition to the non-set condition, although the latch mechanism can be operated from the latch condition to the unlatch condition by the operation of the mechanical identification operation member when the electric actuation mechanism fails during the set condition in which the linkage between the mechanical operation member and the latch mechanism is released. Thus, when an individual operates the mechanical identification operation member to open the vehicle door, enters the vehicle compartment and then closes the vehicle door, the vehicle door cannot be opened from inside the vehicle compartment because the linkage between the mechanical operation member and the latch mechanism is kept released by the engagement-disengagement mechanism.
A need thus exists for a door latch operation device for vehicle which can link the mechanical operation member and the latch mechanism by the operation of the mechanical identification operation member.